The invention relates to a method for routing telecommunication connections (TC connections) to a mobile communications terminal. It also relates to a mobile communications gateway and a mobile communications terminal which are suitable for assisting in implementing the method.
It is known that when the user of a mobile communications terminal is in a foreign country, the mobile communications terminal maintains its connectivity by means of international roaming and hence is able to receive or make calls automatically in a foreign mobile network of the other country. At the same time, mobile network providers levy high roaming charges for international roaming, so that significant costs are associated with using roaming abroad. The same problems arise, although normally involving lower costs, whenever a mobile network is used that is not the home network of a mobile communications terminal in question.
There are also what are known as mobile communications gateways, which provide an interface between one or more mobile telecommunication networks and any other networks, for instance a fixed telecommunication network or an IP network.
A mobile communications gateway is called by the user of another network and forwards the required connection via a mobile communications channel to the mobile network in which the called subscriber is located. For this purpose, the mobile communications gateway implements the functionality of a cellular telephone and effectively acts as a cellular telephone to call the called subscriber. Mobile communications gateways therefore have the same mobile communications modules that are used in mobile communications terminals (cellphones). DE 103 14 144 A1, for instance, discloses such mobile communications gateways.
Here it is provided that a mobile communications gateway contains a multiplicity of SIM cards for the managed mobile communications channels. Any SIM cards from different network operators can be inserted. A SIM card is a plug-in card having an identity (IMSI=international mobile subscriber identity) which uniquely identifies a network subscriber and is the means by which a mobile communications device is assigned to a specific network operator and receives a specific telephone number. In addition, a SIM card comprises a PIN number (PIN—Personal Identity Number), security-related data such as communications keys and security algorithms, user-specific data such as speed-dial numbers, and network-specific data such as the identification of the region in which the user is currently staying. A SIM card personalizes a mobile communications terminal with regard to the user and the network operator and allows the network operator to bill for call charges.
In addition there are what are known as SIM servers. A SIM server provides, at a central location or in a central computer, SIM cards for mobile communication. According to demand and need, a mobile communications gateway requests a SIM card from the central computer and is provided with a SIM card by said computer. This providing of the SIM card for mobile communication is not done physically. The information that identifies a SIM card and reflects the functionality thereof is merely transferred to the mobile communications gateway by remote data transfer. Thus the SIM card is effectively located virtually on a central computer, and the functionality of the SIM card is emulated as required on the mobile communications gateway on the basis of specific information and data that are transferred from the central computer. This allows the use of a central SIM card pool for one or more mobile communications gateways. DE 103 11 980 A1, for instance, describes such SIM servers.